Objectives are to understand how fathers impact children's mental disorders, chronic stress-related physical health conditions, and behavioral problems during emerging adulthood. The study follows a representative sample of 393 Mexican- and European-American intact and stepfather families, recruited from AZ and CA when the children were in 7th grade, tracked with multi-agent reporting and multiple methods in 3 Waves through 10th grade. The study will undertake Wave 4 (12th grade) and Wave 5 (ages 19 - 20). It is guided by a Conceptual Model emphasizing the meanings that children give to fathering behaviors, and that includes biosocial mediators of the effects of fathering. Specific Aims: (1) identify continuities and discontinuities in father behaviors and meanings during emerging adulthood, (2) determine the effects of father behaviors and meanings on mental, physical, and behavioral health, over and above effects of mothering and social- contextual variables, (3) identify the social-contextual variables that predict father behaviors / meanings, (4) determine the role of a set of biosocial mediators (self-esteem, self-efficacy, social support, daily emotional and physiological processes) in the relation between father behaviors / meanings, and outcomes, (5) assess how the above differ by family type, ethnicity, and child gender. Methods employ standardized and open-ended measures, diary records of social and emotional experiences, and salivary cortisol stress responses. It is expected that intra-individual variation in the reactivity of self-esteem, self-efficacy, and perceptions of social support to daily stressful experiences is related to hormone reactivity, and that both are predicted by father behaviors / meanings. Empirical significance includes innovative daily socio-emotional measures, representativeness of the sample (important for public health use of findings), and the longitudinal cohort sequential multi-wave design in which every participant is measured 5 times, but the different intervals allow growth curve modeling of 14 different half-year points, over 10 years (ages 12 to 21). The findings will increase understanding of how fathering affects the physiological, social, emotional, and cognitive lives of emerging adults. Data provide needed information about the health status of Mexican- and European-American youth, and about how parenting affects health which will help guide the design of future interventions aimed at improving children's health. PUBLIC HEALTH RELEVANCE: The findings will increase understanding of how fathering affects the physiological, social, emotional, and cognitive lives of emerging adults. Data provide needed information about the health status of Mexican- and European-American youth, and about how parenting affects health which will help guide the design of future interventions aimed at improving children's health.